1. Field of the Invention
The present invention relates to a novel organosilicon compound, and in particular to an organosilicon compound useful as a curing agent for room temperature organopolysiloxane composition.
2. Description of the Prior Art
Room temperature vulcanizable (RTV) organopolysiloxane compositions used widely as one-pack type adhesives are prepared by adding a curing agent to an organopolysiloxane. The organopolysiloxane composition can be cured at room temperature only by discharging it in the air out of a tube or a cartridge; therefore it has the advantage of ease handling, and is used favorably in extensive fields including electrical/electronics, automotive and construction industries.
The RTV organopolysiloxane compositions are classified into addition-type ones and condensation-type ones according to their curing mechanism. For adhesives, condensation-type ones are mostly used. The condensation-type RTV organopolysiloxane composition is cured and adhered to a substrate while releasing a condensation by-product inherent in the individual curing agent contained. That is, when a condensation-type RTV organopolysiloxane composition is exposed to the air, condensation takes place by moisture in the air to be cured, releasing a gas of e.g, acetic acid, butanoxime, methanol, butylamine, etc. These RTV organopolysiloxane compositions are known as deacetic acid type, deoximation type, dealcoholation type and deamination type ones, respectively, according to the condensation by-product.
Among the condensation-type RTV organopolysiloxane compositions, the deacetic acid type, deamination type and deoximation type ones have the disadvantage that toxic or corrosive, smelly gas is released on curing. On the other hand, the dealcoholation type ones have neither corrosiveness nor smell but have the disadvantage of poor storage stability.
In order to solve these problems, there has been developed an organosilicon compound containing an alkenyloxy group excellent in hydrolyzability, having the general formula: ##STR2## wherein R.sup.3 represents a monovalent hydrocarbon group; R.sup.4 and R.sup.5 are each a hydrogen atom or a monovalent hydrocarbon group, and m represents an integer of from 1 to 4, and disclosed an RTV organopolysiloxane composition containing said organosilicon compound as a curing agent (Japanese Patent Pre-examination Publication (KOKAI) No. 44699/1979).
There has been also developed an organosilicon compound having both of a ketene acetal group and an alkenyloxy group as a curing agent, and an RTV organopolysiloxane composition containing this organosilicon compound is proposed (Japanese Patent Publication (KOKOKU) No. 20464/0988).
However, said organosilicon compound containing the alkenyloxy group disclosed in Japanese Patent Pre-examination Publication (KOKAI) No. 44699/1979 has the disadvantages that it requires long time in synthesis and is expensive itself and that the compositions containing the organosilicon compound is susceptible to color change.
In the case of the composition disclosed in Japanese Patent Publication (KOKOKU) No. 20464/1988, because a silylketeneacetal is synthesized by 1,4-addition of Si-H group to .alpha.,.beta.-unsaturated ester, a smelly carboxylate ester having 2 or more carbon atoms, such as propionates, is released as a condensation by-product on curing.